Thanks Sasha. Fortunately/unfortunately I did realize the default & current behavior of the Ec2Snitch, but my application isn't multi-region capable (yet), so I need to get intra-region redundancy. And having a SingleRegionEc2Snitch that did DC=ec2zone and RACK=??? would be much better for me (for now).
On Wed, Apr 27, 2011 at 9:21 AM, Sasha Dolgy <sdo...@gmail.com> wrote: > Hi William, > > The default behavior of Ec2Snitch is outlined below: > > > http://svn.apache.org/repos/asf/cassandra/trunk/src/java/org/apache/cassandra/locator/Ec2Snitch.java > > // Split "us-east-1a" or "asia-1a" into "us-east"/"1a" and > "asia"/"1a". > String azone = new String(b ,"UTF-8"); > String[] splits = azone.split("-"); > ec2zone = splits[splits.length - 1]; > ec2region = splits.length < 3 ? splits[0] : splits[0]+"-"+splits[1]; > logger.info("EC2Snitch using region: " + ec2region + ", zone: > " + ec2zone + "."); > > ApplicationState.DC = ec2region > ApplicationState.RACK = ec2zone > > We leverage cassandra instances in APAC, US & Europe ... so it's > important for us to know that we have one data center in each 'region' > and multiple racks per DC ... > > -sasha > > On Wed, Apr 27, 2011 at 3:06 PM, William Oberman > <ober...@civicscience.com> wrote: > > It's great advice, but I'm still torn. I've never done multi-region work > > before, and I'd prefer to wait for 0.8 with built-in inter-node security, > > but I'm otherwise ready to roll (and need to roll) cassandra out sooner > than > > that. > > > > Given how well my system held up with a total single AZ failure, I'm > really > > leaning on starting by treating AZ's as DCs, and racks as... random? I > > don't think that part matters. My question for today is to just use the > > property file snitch, or to roll my own version of Ec2Snith that does AZ > as > > DC. > > > > I do increase my risk being single region to start, so I was going to > figure > > out how to push snapshots to S3. One question on that note: is it better > to > > try and snapshot all nodes at roughly the same point in time, or is it > > better to do "rolling snapshots"? > > > > will > -- Will Oberman Civic Science, Inc. 3030 Penn Avenue., First Floor Pittsburgh, PA 15201 (M) 412-480-7835 (E) ober...@civicscience.com
